To prepare cake

1. Preheat the oven to 350 degrees. Spray a bundt pan with baking spray or grease lightly.
2. Combine dry ingredients in the bowl of a stand mixer and mix on low speed for one minute until thoroughly mixed. While stirring on low speed, add small cubes of butter, one at a time, until all 1-1/2 sticks have been added. Continue to mix on low speed for another 1-2 minutes until butter is uniformly dispersed in the dry ingredients.
3. Meanwhile, combine the buttermilk, extracts, and lemon juice in a measuring cup and pour this into the stand mixer bowl, reserving 1/3 cup of the mixture. Beat on medium speed for two minutes until smooth and uniform. Scrape the sides of the bowl and add the remaining milk mixture while mixing on low speed. Slowly pour in the egg whites and eggs, increasing the speed back to medium. Beat for another two minutes, scraping the bowl as needed to ensure that all of the batter is uniform. Add the lemon zest and poppyseeds and mix on low until combined, about thirty seconds.
4. Pour the batter into the prepared pan. Bake in the preheated oven for about 30-35 minutes or until the center of the cake is set and a toothpick comes out clean. Allow to cool in the pan on a cooling rack.

To prepare the glaze

1. Combine all of the ingredients in a small bowl with a whisk. If the consistency is too thin, allow to set out briefly or add additional powdered sugar. Add additional milk if the glaze is too thick. Drizzle over the top of the cooled cake.